Encoding and Decoding of Slot Positions of Events in an Audio Signal Frame

1. An audio decoder for decoding an encoded audio signal comprising an audio signal frame comprising slots and events associated with the slots, comprising: an analysing unit for adapted to analyse a frame slots number indicating the total number of slots of the audio signal frame, an event slots number indicating the number of slots comprising the events of the audio signal frame, and an event state number; a generating unit adapted to generate an indication of a plurality of positions of slots comprising the events in the audio signal frame using the frame slots number, the event slots number and the event state number; and an audio signal processor adapted to generate an audio output signal depending on the indication of a plurality of positions of slots comprising the events in the audio signal frame, using frame slots number, the event slots number and the event state number, wherein audio decoder comprises a hardware implementation.

2. The audio decoder according to claim 1 , wherein the audio decoder is adapted to decode the slot positions of transients in an audio signal frame.

3. The audio decoder according to claim 1 , wherein the analysing unit is adapted to conduct a test comparing the event state number or an updated event state number with a threshold value.

4. The audio decoder according to claim 3 , wherein the analysing unit is adapted to conduct the test by comparing, whether the event state number or an updated event state number is greater than, greater than or equal to, smaller than, or smaller than or equal to the threshold value, and wherein the generating unit is furthermore adapted to update the event state number or an updated event state number depending on the result of the test.

5. The audio decoder according to claim 3 , wherein the audio decoder furthermore comprises a slot selector, wherein the slot selector is adapted to select a slot as a considered slot, wherein the analysing unit is adapted to conduct the test with respect to a considered slot, and wherein the threshold value depends on the frame slots number, the event slots number and on the position of the considered slot within the frame.

6. The audio decoder according to claim 5 , wherein the analysing unit is adapted to conduct the test comparing the event state number or an updated event state number with the threshold value, wherein the threshold value is ( N - h - 1 P ) , wherein N is the total number of slots of the audio signal frame, wherein P is the number of slots comprising the events of the audio signal frame or of a considered portion of the audio signal frame and wherein h is the position of the considered slot within the frame.

7. The audio decoder according to claim 1 , wherein the audio decoder further comprises a frame partitioner, wherein the frame partitioner is adapted to split the frame into a first frame partition comprising a first set of slots of the frame and into a second frame partition comprising a second set of slots of the frame, and wherein audio decoder is further adapted to determine the slot positions comprising the events for each of the frame partitions separately.

8. The audio decoder according to claim 1 , wherein the audio signal processor is adapted to generate the audio output signal according to a first method, if the indication of a plurality of positions of slots comprising the events is in a first indication state, and wherein the audio signal processor is adapted to generate the audio output signal according to a different second method, if the indication of a plurality of positions of slots comprising the events is in a second indication state which is different from the first indication state.

9. The audio decoder according to claim 8 , wherein the audio signal processor is adapted, such that the first method comprises employing a transient decorrelator for decoding a slot, if the first indication state indicates that the slot comprises a transient and wherein the second method comprises employing a second decorrelator for decoding a slot, if the second indication state indicates that the slot does not comprise a transient.

10. An audio encoder for generating an encoded audio signal, comprising: an event state number generator adapted to encode positions of slots comprising events in an audio signal frame by encoding an event state number; and a slot information unit, being adapted to provide a frame slots number indicating the total number of slots of the audio signal frame and an event slots number indicating the number of slots comprising the events of the audio signal frame to the event state number generator; wherein the event state number, the frame slots number and the event slots number together indicate a plurality of positions of slots comprising the events in the audio signal frame; wherein the audio encoder is configured to generate the encoded audio signal comprising information on the event state number, the frame slots number and the event slots number; and wherein audio encoder comprises a hardware implementation.

11. The audio encoder according to claim 10 , wherein the event state number generator is adapted to generate an event state number by adding a positive integer value for each slot comprising an event.

12. The audio encoder to claim 10 , wherein the event state number generator is adapted to generate the event state number by determining a first event substate number for a first frame partition, by determining a second event substate number for a second frame partition, and by combining the first and the second event state number to generate the event state number.

13. A method for decoding an encoded audio signal comprising an audio signal frame comprising slots and events associated with the slots, comprising: analysing a frame slots number indicating the total number of slots of the audio signal frame, an event slots number indicating the number of slots comprising the events of the audio signal frame, and an event state number; and generating an indication of a plurality of positions of slots comprising the events in the audio signal frame using frame slots number, the event slots number and the event state number; generating an audio output signal depending on the indication of a plurality of positions of slots comprising the events in the audio signal frame; using frame slots number, the event slots number and the event state number, wherein the method is implemented using a hardware implementation.

14. A method for generating an encoded audio signal, comprising: receiving or determining a frame slots number indicating the total number of slots of the audio signal frame; receiving or determining an event slots number indicating the number of slots comprising events of an audio signal frame; and encoding the positions of slots by encoding an event state number; wherein the event state number, the frame slots number and the event slots number together indicate a plurality of positions of slots comprising the events in the audio signal frame; and generating the encoded audio signal comprising information on the event state number, the frame slots number and the event slots number; wherein the method is implemented using a hardware implementation.

15. A non-transitory computer-readable medium comprising a computer program for decoding an encoded audio signal implementing a method for decoding an encoded audio signal according to claim 13 .

16. A non-transitory computer-readable medium comprising a computer program for generating an encoded audio signal implementing a method for generating an encoded audio signal according to claim 14 .

17. A non-transitory computer-readable medium comprising an encoded audio signal comprising an event state number, wherein the positions of slots comprising events are decodable according to the method of claim 13 .